I wish I had an answer for you... but I am having EXACTLY the same issue. I can add and edit, but no deleting. I get the same error.
I am hoping to upgrade this coming week to see if that makes any difference, but since I rely on someone else for the upgrading, I frustratingly must wait.
What could possibly be the cause (and please... a solution) for this problem? I can't believe it has been more than three months since your post and there have been no replies! Have you figured something out??